Checking Leak Detection Pump V144 for internal leaks

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Basically, in the following procedure the EVAP system will be filled with smoke, the engine started and the LDP activated using the diagnostic tester VAS 5051 or diagnostic tester VAS 5052. With the LDP activated, and after clearing initial smoke away from the LDP area using compressed air, the system is then filled with smoke again and rechecked for smoke at the LDP filter.

Conditions

Ignition switched off
LDP is visible → Component Locations

Fig 1: Checking Leak Detection Pump (LDP) V144 For Internal Leaks

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Tester hose connected to fuel filler neck
Diagnostic tool VAS 5051 or Diagnostic tool VAS 5052 connected to vehicle
Smoke generator connected to battery

Turn Evaporative Emissions Tester KLI9210DLX valve to "Test" and use smoke generator trigger to fill system with smoke (wait until smoke is coming out of the LDP filter).
Start engine.
From Diagnostic tool VAS 5051 Start-up screen, select "Vehicle self diagnosis".

Fig 2: Display Screen -- Select Diagnosis Function

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Select vehicle system "01 - Engine electronics".

Fig 3: Display Screen -- "01 - Engine Electronics"

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Select Diagnosis Function "04 - Basic settings".

Fig 4: Display Screen -- 04 - Basic Settings

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Input appropriate display group from table below on keypad.

Engine code	Display group
AEB, AEG, AFP, AHA, APH, ATQ, ATW, AUG, AWD, AWM, AWP, AWV, AWW, BDC, BDF, BEV, BGD, BGJ	071
AVH, AZG, BAP, BBW, BDP	202

Press "Q" on keypad to confirm. LDP should activate

If LDP does not activate:

For some vehicles using Display group 202 a similar screen appears indicating "Test Off".

Fig 5: Display Screen -- 04 - Basic Settings, LDP Activated

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Select "Activating" button.

If LDP does not activate:

Check electrical connections to LDP.
Check vacuum source to LDP.

If LDP activates:

Fig 6: Display Screen -- 04 - Basic Settings, LDP Activated ("1" In Position 5)

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A similar screen appears, Test is "ON" (indicated by a "1" in position 5, - arrow - ).

Fig 7: Display Screen -- 04 - Basic Settings, LDP Activated ("1" In Position 1)

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Position 1 - arrow - alternates between "0" and "1" during pump operation.

Fig 8: Display Screen -- 04 - Basic Settings, LDP Activated ("1" In Position 6 And A "0" In Position 8)

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If test is OK:

Indicated by "1" in position 6 and a "0" in position 8 as shown.

LDP has activated and the system is pressurized.

Using a compressed air blow gun, clear area near LDP and LDP filter of any residual smoke.

If the test aborts and DTCs other than for small or large leaks are stored:

Check and repair according to DTC listed in DTC table for appropriate engine code.

When "Check end" is indicated on Diagnostic tool VAS 5051 or Diagnostic tool VAS 5052 :

NOTE:

Only check LDP during "Check end" phase when "Test OK" was indicated.

Use smoke generator trigger to fill system with smoke again.
Check for smoke doming from LDP filter and LDP hose connections.

Smoke coming from filter indicates a faulty LDP
Smoke coming from LDP outlet or hose indicates a faulty hose or clamp

Make repairs as necessary and check with smoke again.

No smoke coming from filter indicates LDP is OK and leak is somewhere else in EVAP system

NOTE:

If the Evaporative Emissions Tester KLI9210DLX is connected in "Test" mode and Basic settings (using Self Diagnosis) and Fault finding are activated, a false "System OK" message may be generated.

If the LDP is OK and a DTC was stored for the EVAP system:

Switch ignition off.
Continue checking EVAP system as follows: